The snoring has been a major nuisance from the past and there have been a number of proposals which were claimed to be effective in suppressing it. Snoring is caused by the vibration of the palatine uvula and other parts of the larynx of a person as he inhales in sleep. Some people have certain larynx structures which are prone to snoring for pathological and other reasons. In any case, when a person is sleeping, the soft palatine uvula and other parts tend to hang in such a manner that the flow of inhaled air is partly obstructed and the snoring noise is produced as a vibration of the wall of the larynx.
According to the apparatus for preventing snoring proposed in Japanese patent publication No. 55-1056 (which is based on U.S. patent application No. 641,226 filed Dec. 16, 1975), penalizing stimulation is applied to a snoring person. This may prevent the snoring, but the person is prevented from obtaining sleep and causes a considerable discomfort to the snoring person.
Japanese patent laid open publication No. 61-164554 discloses a pillow which is designed to vibrate when any snoring is detected. This also applies stimulation to the snoring person and stimulation of an uncomfortable level must be applied to the snoring person for this vibrating pillow to be effective.
Japanese patent publication No. 61-27054 discloses a bed having a floor board which is hinged at one of its edges so as to be able to slightly twist the upper body of the person sleeping in the bed sideways. When snoring is detected, the floor board is lifted by one step. The floor board is lifted higher by increments as long as the snoring continues. If the snoring ceases for a certain time interval, for instance three minutes, the floor board is lowered by one step. If the snoring has completely stopped, the floor board is lowered by increments until the floor board returns to its initial horizontal position.
Japanese utility model publication No. 61-203013 discloses a pillow having a plate which is hinged at one of its edges and adapted to twist the head of the sleeping person sideways. The plate pushes the head of the sleeping person when a snoring noise is detected, but this pillow is provided with a timer which restores the plate to its initial horizontal position after elapsing of a certain time interval.
These proposals are not satisfactory because they cause substantial stimulation to the sleeping person and the snoring of the person is suppressed at the expense of the sleep or the comfort of the snoring person. Further, in these conventional devices for controlling the snoring of a sleeping person, accurate detection of snoring is not possible because the detection is based on the sound level of the snoring, and other noises could erroneously activate the device to the considerable discomfort to the innocent person who may be sleeping without snoring.